Core drills with a detachable end portion are well known and on example is found in GB686372A. Core drills are normally used with a cooling liquid, and in order to make the liquid reach the parts of the drill where the need for cooling is the largest, it is important to achieve an effective sealing between the end portion and the drill bit. It is also simplifying if, once the end portion has been removed, full access is gained to the full inner diametre of the drill bit, as this facilitates removal of the drill core. The drill bit itself is often thin walled, so achieving both these advantages with one and the same design is hard to achieve.
An object of the invention is therefore to provide a core drill with a detachable end portion where access to the full inner diameter of the drill bit is gained once the end portion is removed.
These and other objects are attained by a core drill with a detachable end portion according to the characterising portion of the independent claim.